Summary of Radon Surveys in North Dakota 1988-1993


The North Dakota Department of Health has utilized the United States Environmental Protection Agency's State Indoor Radon Grant (SIRG) and other Federal programs to help operate the State's Radon Program since 1988. This funding has been critical to the success of the State's Radon Program. Through this assistance, the Department completed radon surveys of homes, clusters, daycare facilities, schools and homes served by the Women, Infants and Children (WIC) Program during the years 1988-1993.

This report contains the results of each of these five surveys. It includes information on the number of samples in each survey, the arithmetic mean, the arithmetic standard deviation, the percentage of samples greater than 4 and 20 pCi/l and other data related to the surveys. The Department has more detailed reports available for each of these surveys. This detailed information is available upon request.

The summary and conclusion section compares the data from all of the five surveys.

Table of Contents

Home Survey
Cluster Survey
Day Care Survey
School Survey
WIC Survey
Summary (read me first)


During the years 1988-1993, the North Dakota State Department of Health and Consolidated Laboratories in partnership with the U.S. EPA conducted surveys of radon in homes, daycare facilities, schools, and homes served by the Women, Infants, and Children (WIC) program. The log normal curves of the surveys show that the WIC homes curve, day cares curve, and homes curve could be considered a single line given the precision and accuracy of radon testing. The cluster curve which is a subset representing radon testing in and around those homes from the 1988 homes survey that were greater than 20 pCi/l is parallel to the homes curve. As would be expected, the cluster curve is greater in magnitude. The school curve is parallel to the homes curve, however, is less in magnitude. The air handling equipment of large buildings such as schools is thought to be the factor causing the lower concentrations of radon.


The North Dakota Department of Health (NDDH) expresses appreciation for contributions from the following:

The Research Triangle Institute of Research Triangle Park, North Carolina, who were the contractors for the original Home Survey of 1988.

The Radon Project of Pittsburgh, Pennsylvania, laboratory for the Day Care Survey, October 1990 through April 1991.

The Niton Corporation of Bedford, Massachusetts, that performed as the Department's laboratory, October 1991 through April 1992.

The Home Radon Detection, Inc. (HRDI) was the Department's laboratory during the first two years of school testing.

The Radon Testing Corporation of America (RTCA) analyzed the samples for the School Survey the last year of the School Survey.

The Environmental Protection Agency, Region VIII, Denver, Colorado, for providing funding and technical assistance during 1988-1993.

The homeowners, day care operators, school personnel, and the WIC participants, without whose cooperation these surveys could not have been done.


In 1988, the North Dakota Department of Health, U.S. EPA Region VIII, and the Research Triangle Institute of Research Park, North Carolina tested radon in approximately 1600 homes in North Dakota. The results from that survey caused considerable concern among North Dakotans. The mean radon concentration was 7.0 pCi/l and the percent of samples greater than 4 pCi/l was 63%. All of North Dakota was placed in zone one, meaning the entire State had a potential for radon concentrations greater than 4 pCi/l in homes.

A cluster survey around those locations greater than 20 pCi/l was completed in 1989. A school survey was begun in 1989 and completed in 1992. The WIC home survey was completed in 1993. The Department is presently preparing to conduct a survey for radon in private wells and the home that the well serves. This survey is expected to be completed during the 1993-1994 radon testing season.

The survey reports cover the Department's survey work for the years 1988-1993.

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